Abstract 3249: Extended Echocardiographic Follow-up in Patients Undergoing Cardiac Resynchronization Therapy
Background: Reverse remodeling has been identified as the primary mechanism of improved outcome in heart failure patients undergoing cardiac resynchronization therapy (CRT). We sought to describe the long-term course of LV remodeling induced by CRT, adjusting for the confounding effect of patient loss due to disease.
Methods: 313 consecutive patients who underwent CRT with available baseline echocardiograms and subsequent clinical and echocardiographic follow-up were included in the analysis. Long-term follow-up included all-cause mortality, heart transplantation and implantation of a left ventricular assist device. Sequential changes in left ventricular end systolic volume index (LVESVi) were evaluated by linear mixed model analysis.
Results: Patients with uneventful survival had lower baseline LVESVi (Δ=8.6 ml/m2, p<0.0001) and developed a decrease in LVESVi by −0.11ml/m2/day during first 6 months whereas LVESVi remained unchanged in patients with adverse events (p <0.0001, figure 1⇓). Beyond 6 months, LVESVi remained unchanged in patients with uneventful survival while LVESVi continued to increase in those with adverse events at a rate of 0.01ml/m2/day (p< 0.0001). Predictors of reverse remodeling were non-ischemic etiology, female gender, and a wider QRS duration (p<0.0001, p=0.014 and p=0.001 respectively). In the majority of patients, 6 months indicates a breakpoint after which reverse remodeling becomes significantly less pronounced.
Conclusion: CRT patients with uneventful survival show a significant decrease in LVSVi at 6 months and maintain this response at long-term. Those with adverse outcome are characterized by LV dilatation in spite of CRT.